Directional toroidal dipoles driven by oblique poloidal current flows in plasmonic meta-atoms

TL;DR

This paper explores how to excite directional toroidal dipoles in plasmonic meta-atoms by controlling oblique poloidal currents, revealing new modes enabled by asymmetric designs.

Contribution

It introduces a novel approach to generate directional toroidal dipoles through structural asymmetry and oblique poloidal flux control in plasmonic meta-atoms.

Findings

Multiple toroidal modes with opposite poloidal currents are formed.

Asymmetric design enables directional excitation of toroidal dipoles.

The approach extends understanding of non-radiating charge-current configurations.

Abstract

The toroidal dipole is an exquisite electromagnetic momentum apart from the classical multipoles family that can be localized and squeezed in an extremely tiny spot. This mode, in optical nanosystems, can be particularly distinguished as a non-radiating charge-current configuration, manifests in a head-to-tail fashion. Here going beyond conventional toroidal dipoles, we explained the possibility of the excitation of directional toroidal dipoles in plasmonic meta-atoms driven by controlling the oblique poloidal fluxes. We showed that the unique structural properties of the proposed asymmetric design lead to the formation of multiple toroidal modes with opposite poloidal current flows.